Internal combustion engines ignition systems



9, 1963 A. BUNODIERE ETAL INTERNAL COMBUSTION ENGINES IGNITION SYSTEMS Filed June 1'7, 1960 INTERNAL coMsUsrioN ENGKNES'? tortures .SYSIEM utiiaawsrtrurranee; as'ngaers tastiornueg ms one gi elegraphie Sans Fit,

es M ,;iiee-rme-i7,--1ase;setriv as ii Ciaimfiprierit-y," appiieation- Fri done 22; 1939 2 Claims. (Q1. 315-265) The present invention relates to ignition devices for internal combustion engines. More particularly it is an object of the invention to provide an improved ignition generator of the electronic type.

An ignition system according to the invention comprises a 13.0. voltage source a delay line and the primary winding of a pulse transformer connected in series, a control device having thyratron control characteristics connected between the input of said line and said primary winding, the control electrode of which is connected to a pulse generator, the secondary winding of the pulse transformer being connected to an ignition distributor.

Preferably the control device is of the multi-junction semiconductor type.

The invention will be best understood from the following description and appended drawing given by way of a non limitative example.

In this drawing,

FIG. 1 illustrates one embodiment of an ignition generator according to the invention; and

FIG. 2 shows waveforms at dilferent points of the circuit.

According to the embodiment shown in FIG. 1, a battery 1 is connected in series with an inductance coil 2, a rectifier diode 3, a delay line 4 and the primary winding 5 of a pulse transformer 6 having a secondary winding 7. A multi-junction semi-conductor device 8, which has the characteristics of a thyratron and comprises a control electrode 9, or another device having such characteristics, is connected in parallel across line 4 and primary Winding 5. A semiconductor device of this type can withstand peak currents of about 150 a. and reverse voltages of about 40 v. A diode 10 is connected in parallel with semi-conductor device 8. The control electrode 9 is connected to one terminal of a circuit breaker 12 through an RC circuit comprising a resistor '13 and a capacitor 11 and having a suitable time constant for obtaining the pulses applied to electrode 9 through the breaker 12. The latter may be of either any conventional type used in motor car engine ignition systems, or a make and break device of the magnetic type, for example comprising a rotary magnet and a moving coil or coil ensemble, such as that disclosed in the French Patent 1,183,698.

The secondary winding 7 of pulse transformer 6 is connected to a distributor 15 of the ignition system. Distributor 15 is mechanically or otherwise tied to the engine 16 in order to operate in synchronisrn and in phase therewith.

For example in the FIG. 1, the engine 16 operates two gear-boxes 17 and 18, the gear-box '-17 being connected between the engine 16 and the distributor 15 and the gearbox 18 between said gear-box 17 and the circuit-breaker 12 with convenient reduction or multiplication ratios. The distributor 15 has four contact-studs 151, 152, 153 and 154 respectively connected to the four spark-plugs (not shown) of the engine.

The operation of the system shown in FIG. 1 will be explained with reference to the diagrams illustrated in FIG. 2 and which show the voltages appearing at the main points of the circuit of FIG. 1, these voltages being and ea eares t arnets asaare

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said distributor 15 rotate once studs 151 and 154 and said breaker 12 is four times closed and four times open. Battery 1 charges the condeners of the artificial line 5 to a potential 2U, the potential across the terminals of this battery being U. Pulses A of alternating polarities are applied to the control electrode 9 of the semi-conductor crystal 8 by breaker 12. Whenever a pulse of a suitable polarity is applied to electrode 9, element 8 becomes conductive and causes the capacitors of the artificial line 4 to discharge. The voltage at point B is shown at B in FIG. 2. Each time this occurs the voltage at B, which was equal to 2U, falls nearly instantaneously to zero, then will increase, in a semi-sinusoidal way, up to 2U, to collapse again when the next pulse of the same polarity occurs. Line 4 also is a pulse shaping circuit and rectangular pulses occur at point C. Then voltage is raised by transformer 6 and the secondary winding 7 ultimately delivers pulses of the shape shown at D. Diode 10 avoids the harmful effects of the reverse current in the semi-conductor thyratron 8. Transformer 6 may, according to a well-known technique, be pre-magnetized by means of a permanent magnet.

Among the advantages presented by the electronic ignition device of the invention, the following may be noted:

Accurate determination of the ignition periods Excellent operation of the ignition, even when the impedance or the spark plug is low.

It is to be understood that the invention is in no way limited to the embodiment described and illustrated, which has been given only by way of example.

What is claimed is:

1. An ignition system for internal combustion engine having spark-plugs, comprising in combination: rneans for generating a pulse waveform voltage having a controllable recurrent period; means controlled by the rotation of said engine for tying said recurrence period to the period of said rotation; a multi-junction semi-conduc tor switching device having an input for receiving said pulsed voltage and an output; a delay line device, a transformer having a primary and a secondary Winding; said delay line device and said primary winding being series connected to said output of said multi-junction semiconductor switching device; a constant DC. current voltage source for energizing said ignition system; arectifying diode series connected between said constant DC voltage source and said delay line device, for preventing the dis charge of said delay line in said source; an ignition rotating distributor having contact studs, means for connecting said studs to said spark-plugs, and means for tying the rotation of said distributor to the rotation of said engine.

2. An ignition system for internal combustion engine having spark-plugs, two terminal inputs, means for connecting said terminals to a DC. constant voltage source, said system comprising in combination: across said terminals, a circuit-breaker, means controlled by said engine for operating said circuit-breaker in synchronism With the rotation of said engine for generating a crenel waveform voltage having a period tied to said rotation; deriving means having an input for receiving said crenel waveform voltage and an output, said deriving means comprising a capacitor and a resistor connected in series across said circuit-breaker and having a junction point at said output of the same deriving means; a control device having thyratron control characteristics, having an input and an output; means for feeding to said input of said control device the pulsed voltages issued at said output of said deriving means; a delay line device having an input and an ouput, said input of said delay line device being connected to said output of said control device; a rectifier diode and an inductance coil series connected between one of said terminals and said delay line device for preventing the discharge of said delay line in said source; a pulse transformer having a primary and a secondary Winding, said primary winding being series connected with said output of said delay line device and with the other of said ter- 4 i v minals; a rectifier diode bridge connected with said delay line and said primary for clipping the negative pulse of said delay line; a rotating distributor connected to said secondary winding; means for tying the rotation of said distributor to the rotation of said engine and means for connecting said distributor to the spark-plug of said engine.

References Cited in the file of this patent UNITED STATES PATENTS 2,552,989 Mayer May 16, 1951 2,596,142 Gerwin May 13, 1952 2,967,275 Brown Jan. 3, 1961 

1. AN IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINE HAVING SPARK-PLUGS, COMPRISING IN COMBINATION: MEANS FOR GENERATING A PULSE WAVEFORM VOLTAGE HAVING A CONTROLLABLE RECURRENT PERIOD; MEANS CONTROLLED BY THE ROTATION OF SAID ENGINE FOR TYING SAID RECURRENCE PERIOD TO THE PERIOD OF SAID ROTATION; A MULTI-JUNCTION SEMI-CONDUCTOR SWITCHING DEVICE HAVING AN INPUT FOR RECEIVING SAID PULSED VOLTAGE AND AN OUTPUT; A DELAY LINE DEVICE, A TRANSFORMER HAVING A PRIMARY AND A SECONDARY WINDING; SAID DELAY LINE DEVICE AND SAID PRIMARY WINDING BEING SERIES CONNECTED TO SAID OUTPUT OF SAID MULTI-JUNCTION SEMI- 